I don't think this is a huge table, and hence you're probably best
going (as others have suggested) with a hash table of some sort. Your
other alternative if it gets up to a larger size would be a decary
tree. Use each digit from the number you're looking up to index the
tree. Then you have a nice O(log(n)) solution, which may or may not
be better than the amortized constant of the hash table (depending on
the input, and the quality of your hash function).
Bob
On 13 Mar 2008, at 21:11, Karan Lyons wrote:
What's the best way to lookup something from a huge table?
I'm trying to write a piece of code that checks weather data given
a zipcode. But I first need to change that zipcode into another
format in order for it to work with the online service I'm querying.
For example:
1) User inputs zipcode 02139.
2) Application looks up zipcode in table and finds that 02139 is
USMA0007
3) Application uses code USMA0007 to query the online service.
The table itself is pretty simple: It's just two columns, one with
every zipcode in the US, and the other with the corresponding
weather code. But there are 41,805 zipcodes in the US, so I'm not
sure of the best way to implement this. The table only needs to be
queried once, after that I can store the weather code in memory.
What's the best way to do this? Thanks for your help!
